package com.umerclass.utils;

import android.media.AudioFormat;
import android.media.AudioRecord;

import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;

/**
 * Created by HaoGuibao
 * Date 2016/8/26.
 * Description :pcm格式的音频转换为wav格式的工具类
 */
public class PcmToWavUtil {
 private int mBufferSize; //缓存的音频大小
 private int mSampleRate = 8000;// 8000|16000
 private int mChannel = AudioFormat.CHANNEL_IN_STEREO; //立体声
 private int mEncoding = AudioFormat.ENCODING_PCM_16BIT;
 
 public PcmToWavUtil() {
  this.mBufferSize = AudioRecord.getMinBufferSize(mSampleRate, mChannel, mEncoding);
 }
 /**
  * @param sampleRate sample rate、采样率
  * @param channel channel、声道
  * @param encoding Audio data format、音频格式
  */
 public PcmToWavUtil(int sampleRate, int channel, int encoding) {
  this.mSampleRate = sampleRate;
  this.mChannel = channel;
  this.mEncoding = encoding;
  this.mBufferSize = AudioRecord.getMinBufferSize(mSampleRate, mChannel, mEncoding);
 }
 /**
  * pcm文件转wav文件
  *
  * @param inFilename 源文件路径
  * @param outFilename 目标文件路径
  */
 public void pcmToWav(String inFilename, String outFilename) {
  FileInputStream in;
  FileOutputStream out;
  long totalAudioLen;
  long totalDataLen;
  long longSampleRate = mSampleRate;
  int channels = 2;
  long byteRate = 16 * mSampleRate * channels / 8;
  byte[] data = new byte[mBufferSize];
  try {
   in = new FileInputStream(inFilename);
   out = new FileOutputStream(outFilename);
   totalAudioLen = in.getChannel().size();
   totalDataLen = totalAudioLen + 36;
 
   writeWaveFileHeader(out, totalAudioLen, totalDataLen,
     longSampleRate, channels, byteRate);
   while (in.read(data) != -1) {
    out.write(data);
   }
   in.close();
   out.close();
  } catch (IOException e) {
   e.printStackTrace();
  }
 }
 /**
  * 加入wav文件头
  */
 private void writeWaveFileHeader(FileOutputStream out, long totalAudioLen,
                                  long totalDataLen, long longSampleRate, int channels, long byteRate)
   throws IOException {
  byte[] header = new byte[44];
  header[0] = 'R'; // RIFF/WAVE header
  header[1] = 'I';
  header[2] = 'F';
  header[3] = 'F';
  header[4] = (byte) (totalDataLen & 0xff);
  header[5] = (byte) ((totalDataLen >> 8) & 0xff);
  header[6] = (byte) ((totalDataLen >> 16) & 0xff);
  header[7] = (byte) ((totalDataLen >> 24) & 0xff);
  header[8] = 'W'; //WAVE
  header[9] = 'A';
  header[10] = 'V';
  header[11] = 'E';
  header[12] = 'f'; // 'fmt ' chunk
  header[13] = 'm';
  header[14] = 't';
  header[15] = ' ';
  header[16] = 16; // 4 bytes: size of 'fmt ' chunk
  header[17] = 0;
  header[18] = 0;
  header[19] = 0;
  header[20] = 1; // format = 1
  header[21] = 0;
  header[22] = (byte) channels;
  header[23] = 0;
  header[24] = (byte) (longSampleRate & 0xff);
  header[25] = (byte) ((longSampleRate >> 8) & 0xff);
  header[26] = (byte) ((longSampleRate >> 16) & 0xff);
  header[27] = (byte) ((longSampleRate >> 24) & 0xff);
  header[28] = (byte) (byteRate & 0xff);
  header[29] = (byte) ((byteRate >> 8) & 0xff);
  header[30] = (byte) ((byteRate >> 16) & 0xff);
  header[31] = (byte) ((byteRate >> 24) & 0xff);
  header[32] = (byte) (2 * 16 / 8); // block align
  header[33] = 0;
  header[34] = 16; // bits per sample
  header[35] = 0;
  header[36] = 'd'; //data
  header[37] = 'a';
  header[38] = 't';
  header[39] = 'a';
  header[40] = (byte) (totalAudioLen & 0xff);
  header[41] = (byte) ((totalAudioLen >> 8) & 0xff);
  header[42] = (byte) ((totalAudioLen >> 16) & 0xff);
  header[43] = (byte) ((totalAudioLen >> 24) & 0xff);
  out.write(header, 0, 44);
 }
}
